The skeletal dysplasias are a heterogenous group of disorders which result in disproportionate short stature and/or skeletal deformities. This study involves a multidisciplinary investigation of the clinical, genetic, morphologic, biochemical and molecular characteristics of the skeletal dysplasias. In the past year, these studies have resulted in the identificaion of the genes responsible for several dysplasias, including pseudoachondroplasia and achondrogenesis.